This contract is to provide the support services for NLM Toxicology files. The project involves: Task I: Maintaining SUPERLIST files; tracking a and supplying the regulatory data on chemicals of various government agencies; and providing toxicology-related data for Hazardous Substance Candidate file. Task II: The regeneration and augmentation of the ChemID or ChemLINE; and providing chemical structures for SUPERLIST and HSDB chemicals using CHEMBASE software. Task III: Programming to support the update of RTECS on TOXNET. Task IV: Programming to support the TOXNET DART file - Elhill TOXLINE format conversion.